DESCRIPTION: The Center on Dietary Botanical Supplements at Iowa State University (ISU) and the University of Iowa (UI) will link two traditionally strong complementary institutions and focus their effort on important research on botanical supplements. This multidisciplinary center will include scientists from horticulture, botany, biochemistry, molecular biology, oxicology, chemistry, medicinal pharmacology, nutrition, epidemiology, clinical medicine and statistics. We have chosen to study Echinacea and hypericum becase they are two of the most commonly used herbs by consumers in the united States; there is substantial evidence for potential health benefits; both genera are readily grown in Iowa; and our affiliated North Central Regional Plant Introduction Station maintains the national's germplasm repository for Echinacea, conserving all known species in the genus. These herbs also offer different models for research on botanical supplements and for expanding our understanding of the potential health benefit of herbs. Echinacea has potential broad bioactivity but little is known regarding the active constituents and nothing is known regarding mechanisms of action. In contrast, active constituents have been identified from hypericum and there is growing information on mechanism. The proposed center includes five projects and two cores. Project 1 will focus on understanding the genetic, developmental, and environmental diversity of Echinacea and Hypericum. Project 2 will provide the critical understanding of the chemical constituents in of Echinacea and Hypericum. Project 3 will seek to understand the bioactivity of Echinacea and Hypericum, the constituents responsible for bioactivity and the bioavailability of the key constituents in human subjects. Project 4 will conduct epidemiological studies of dietary botanical supplements. Project 5 will conduct phase 1 and II clinical trials in HIV positive subjects using extracts from Echinacea and Hypericum. Core A, germplasm and cultivation, will provide standardized plant materials of known biological origin produced under controlled conditions. The planning and administration Core (Core B) will facilitate overall management of the Center, coordinate the statistical component and increase research on dietary botanicals at UI and ISU through provision of development funds and pilot projects. This center will serve as a national resource and interact with other institutions.